1. Field of Invention
The present invention relates to a technology field of reinforcing base facilities such as tunnels, foundations and side slopes, and more particularly to a method for grouting a polymer supporting anchor rod utilized in foundation pits, tunnels, side slopes, etc.
2. Description of Related Arts
In China, the development of the geotechnical anchorage technology began in late 50's of the 20th century, and at that time, the technology was mainly utilized in mine tunnel supporting engineering. In 60's, an anchor rod supporting technology was widely used in railway tunnel, water conservancy, side slope and underground engineering. Since 1970's, the earth anchor rods were widely used in deep foundation pit retaining engineering. Applications of anchorage technologies effectively guarantees the stability of an internal stress field of a rock and soil mass, improves an internal mechanical state of the rock and soil mass, inhibits expansion of plastic zones, transforms a passive supporting to an active supporting and increases the stability of the rock and soil mass and structures. In addition, the application of the anchorage technologies can also reduce the project cost, shorten the construction periods, and reduce the maintenance cost after completion of engineering, and has the advantage of improving durability and the stability with a single step. At present, the geotechnical anchoring technology has been widely applied in the side slope, foundation pit, mine, tunnel and underground engineering, hydraulic structures and anti-floating engineering.
When it comes to a selection of anchoring materials, conditions of surrounding rocks and purposes must be considered in such a manner that an anchoring force is fully obtained along an anchorage length. Necessary requirements for the anchoring material are that the material is easy to fill, the early-term and long-term anchoring force are high enough and has sufficient durability, the material can be glued firmly to a gluing layer of a basic body and a rebar needing anchorage and is easy to build, economic benefits are considerable, etc. The conventional anchoring materials mainly comprise mortar, cement, resin, etc. Although the conventional cement anchoring material in the world is widely utilized in engineering practices, there are still some problems therein such as complex processing of water-contained cement volume, high costs, inconvenient transportation and storage, and installation needing mechanical agitation. A quality of the supporting with an immersed cement volume is lowered and wastes arises because most of additives added in the cement are deliquescent materials, the additives accelerates moisture and metamorphism of the cement, and thus shortens storage periods, lowers performance and even loses efficacy. Additionally, the conventional cement anchoring material in the world utilizes a fixed composition and mixture ratio, and adjustments of a gelation time and strength at scene freely is difficult, therefore, the material can not adapt to changeable characteristics of the geotechnical engineering. While application of a resin bonded anchor is limited because the resin material is poisonous, flammable, easy to aging, and high in price.
In recent years, in order to improve mechanical properties of grout, various modified materials have been developed or introduced for the anchorage, most of the modified materials belong to the category of modified cement mortar. In fact, mixing ordinary cement mortar grout with the modified materials can not change the essence of water reactions, if water is involved, shrinkage after drying happens, anti-seismic and anti-crack capabilities are not sufficient and an improvement of the anchoring force is limited. With rapid developments of the pit foundation, tunnel and side slope engineering, conditions of the rock and soil mass for anchorage engineering are more and more complex and varied, engineering standards are stricter and stricter, and demands for anchorage performance are higher and higher. The conventional anchoring materials like cement mortar are difficult to adapt to requirements of the development of the anchorage technology because of the limited anchoring force, mediocre mechanical performance and insufficient deformation ability. Therefore, the development of a new material without the water reaction has important relevance on improving anchorage effects, widening application fields of the anchorage, and meeting requirements of the complex conditions of the rock and soil mass.
A polymer grouting technology is a foundation reinforcing technology rapidly developed in 1970's. The technology enhances the foundation and filling hollows by grouting a polymer materials into the foundation and taking advantage of a characteristic that the polymer materials expands and solidifies rapidly after chemical reaction happens. At present, the polymer grouting technology is mainly utilized in foundation reinforcements of industrial and civil construction and road maintenance. The inventor combines a non-water reacted two-component expansive polymer grouting material with the anchorage technology according to development requirements of foundation, tunnel and side slope supporting anchorage and deficiencies of the conventional anchoring technology in China as well as provides a new polymer grouting anchorage technology. The innovation has not been reported.